객관식
Which of the following is the strongest acid listed?
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2. Water
Acid Dissociation Constant
Multiple Choice
Calculate Ka of proprionic acid (CH 3CH2CO2H) if [CH3CH2CO2H]eq = 0.2 M & [CH3CH2CO2-]eq = 1.62 x 10-3 M.
A
Ka = 1.3 x 10-5
B
Ka = 7.8 x 10-10
C
Ka = 3.9 x 10-12
D
Ka = 5.1 x 10-4
검증된 단계별 안내1
Understand that the acid dissociation constant (Ka) is a measure of the strength of an acid in solution. It is defined by the equilibrium concentrations of the acid and its dissociated ions.
Write the chemical equation for the dissociation of propionic acid: CH3CH2CO2H ⇌ CH3CH2CO2- + H+.
Use the expression for Ka: Ka = [CH3CH2CO2-][H+]/[CH3CH2CO2H]. Note that [H+] is equal to [CH3CH2CO2-] at equilibrium for a weak acid.
Substitute the given equilibrium concentrations into the Ka expression: Ka = (1.62 x 10^-3 M)(1.62 x 10^-3 M)/(0.2 M).
Calculate the value of Ka using the substituted values, ensuring to maintain the correct units and significant figures throughout the calculation.
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